Just a disclaimer I have Welcome Amiibo so if you're getting the original version it may be slightly different.
Trees and saplings don't die in ACNH but they do in all older games as far as I know. If you're planting a tree you will need to make sure it's on grass/snow (not dirt/animal tracks I believe), got a bit of space and there's not a building casting a shadow on it.
If you are the kind of person who doesn't get the opportunity to play every day, the game progression feels quite slow (without TT), but I believe it's worth it to wait. I got NL for Christmas this year and I just got Kicks and Harriet, haven't paid off my debt for the 5th out of 19 expansions (at least there are 19
for the WA update and 18 in original), and I'm still paying for my first PWP. That might be because I've been pretty busy lately irl though. Just a heads up that it might take time to get where you wanna be.
Idk if you feel like it's worth waiting for or not, but feel free to TT if need be
Other than that it's a pretty straightforward game, some other tips:
1. The pocket space is painfully small compared to NH, but you can stack fruit up to 9 manually by dragging them together, I think that's the only thing you can stack
2. The questions rover asks you at the beginning determine what your face looks like. Looking at face guides online is really helpful so that you know what you're making yourself look like
3. Tortimers island is very OP for getting bugs/fish to sell and the tours are a blast, but don't leave without putting stuff you want to take home in the take-home basket. Also on some tours if you see fruit you don't have yet and if it doesn't affect your gameplay it's a good idea to bring some home to grow

4. upgrade the nooklings shop as much as you can (by buying stuff) to get slingshot in early game and balloon furniture
Good luck and happy gaming :3